Nowadays, the windshield wiper most used in automobiles can be categorized into two types of “support framed wiper” and “support frameless wiper”, wherein: the “support framed wiper” has been used on a mass scale in all old cars for being developed quite a long time; However, the “support frameless wiper” has been lately used in new cars with trend to gradually replace the obsolete “support framed wiper” overall owing to its better scrubbing effect and longer service life as well as environment protection effect in reducing material of support frame. Besides, most of the head type of the wiper arm matched said “support framed wiper” are hook type; A special connector of unitary plastic extruding molded body must be adopted to joint said “support framed wiper” with hook-type wiper arm into an integral unit so as to have the expected scrubbing effect on the windshield, such as USA issued patents disclosure in numbers of U.S. Pat. No. 6,640,380, U.S. Pat. No. 6,591,445, U.S. Pat. No. 6,539,576, U.S. Pat. No. 6,332,236, U.S. Pat. No. 6,161,249, U.S. Pat. No. 5,937,474 and U.S. Pat. No. 5,611,103.
Moreover, the head type of the wiper arm matched said “support frameless wiper” is different from the wiper arm to the wiper arm as the structure of said “support frameless wiper” is completely different from that of said “support framed wiper”; An exclusive connecting device for each head type of the wiper arm must be contrived to joint with said “support frameless wiper”, such as USA patents issued in numbers of U.S. Pat. No. 6,675,432, U.S. Pat. No. 6,799,348, U.S. Pat. No. 6,904,639, U.S. Pat. No. 6,874,195, U.S. Pat. No. 6,810,556, U.S. Pat. No. 6,643,889, U.S. Pat. No. 6,668,419, U.S. Pat. No. 6,687,948, U.S. Pat. No. 6,782,581, U.S. Pat. No. 6,836,926 and U.S. Pat. No. 6,910,244 as well as patent applications published in numbers of US2004/0216260, US2004/0010882, US2004/0211021, US2005/0011033, US2004/0025280, US2004/0098821 and US2005/0039292; All disclosed that the exclusive connecting device is adopted for each special different head type of the wiper arm.
However, for those huge number of consumers, who owns old car with said “support framed wiper” and wishes to replace into “support frameless wiper”, can not obtain what is desired because no suitably exclusive connector for the traditional hook-type wiper arm on their cars to joint with said “support frameless wiper”; For consumer, who insists on replacing into “support frameless wiper”, he must discard the existing hook-type wiper arm and replace into exclusive head type of wiper arm suitable with “support frameless wiper” on a higher expense basis; Therefore, some factories recently provide special connecting devices able to joint “support frameless wiper” with conventional hook-type wiper arm so as to remedy the aforesaid drawback as well as to reduce the economical burden of the consumers. The structure of such connecting device is shown in the FIGS. of 1 through 7 and 16, comprising a base 20, a frame hood 30, a pivotal cover 40 and connector 50. Said base 20, which being pressed of rigid metal, has a pair of horizontal clipping grooves 21 longitudinally facing each other and parallel juxtaposed apart at the bottom section of both side panels; A pair of symmetrical and parallel vertical left side panel 23 and right side panel 24 of same shape are erected apart on the both edges of the top surface 22, which connecting with both of said clipping grooves 21; And, a horizontal cross fixing spindle 25 transversely straddles over said left side panel 23 and right side panel 24; By means of said clipping grooves 21, said base 20 can be fixedly clipped on the elastic metal strip 11 of the support frameless wiper 10; Said frame hood 30, which being an unitary extruding molded body of a plastic material, has a pair of symmetrical and parallel vertical left hood panel 31 and right hood panel 32 of same shape are erected apart on its both sides; For both said left hood panel 31 and right hood panel 32, a horizontal cross mating spindle 33 transversely straddles over their front end, a vertical mating plate 34 is erected at their rear end, and a pair of symmetrical and parallel left inset groove 35 and right inset groove 36 of same shape with opening facing downwards are formed apart on inside at their middle section; A pair of left baffle lump 37 and right baffle lump 38 are set on inside at the top edges of both said left inset groove 35 and right inset groove 36; And, two pair of snap-fitting noses 39 are set on inner sides at the bottom edges of both said left hood panel 31 and right hood panel 32 corresponding to the opening direction of said left inset groove 35 and right inset groove 36; By means of said left inset groove 35 and right inset groove 36 as well as four snap-fitting noses 39, said base 20 with left side panel 23 and right side panel 24 can be fixedly inset inside of said frame hood 30 (as shown in g view of the FIG. 16); Said pivotal cover 40, which freely pivoting to cover on said frame hood 30, has a tubular groove 41 disposed on one short end and a pair of elastic snap-fitting barbs 42 erected at both side panels on another short end; By means of coupling said tubular groove 41 with said mating spindle 33 on said frame hood 30, said pivotal cover 40 can freely lift up and close down over top surface of the front portion at said frame hood 30 with said mating spindle 33 as fulcrum (as shown in A and B views of the FIG. 6); Said connector 50, which being an unitary extruding molded body of a plastic material similarly as conventional connector of the said “support framed wiper”, to be inset between said left side panel 23 and right side panel 24 of said base 20, comprises a pair of symmetrical and parallel vertical left side plate 51 and right side plate 52 of same shape are erected apart on its both sides with a horizontal body plate 53 straddling over them to form an integral body; Wherein, a pair of buckling noses 54 are juxtaposed apart on the inside at the front ends of said left side plate 51 and right side plate 52 so as to form a space for just accommodating the hook head 61 of the hook-type wiper arm 60; Moreover, a round groove 55 with opening facing downwards is formed on the horizontal body plate 53, which locating at the middle section of said left side plate 51 and right side plate 52, to be coupled with said fixing spindle 25 on said base 20 so as to enable itself to pivot on said base 20 within a limited angle.
The shown in the FIG. 6 to FIG. 9 is the mounting assembly operation of said connecting device used in the traditional hook-type wiper arm 60: First, apply a force on said pivotal cover 40 by one finger to deform said two elastic snap-fitting barbs 42 so as to detach the clipping from said left inset groove 35 and right inset groove 36 (as shown in view B of the FIG. 6); By said mating spindle 33 means of fulcrum, said pivotal cover 40 can be freely lift up away said frame hood 30 (as shown in view D of the FIG. 7); Next, insert said hook head 61 of the hook-type wiper arm 60 between said left side plate 51 and right side plate 52 of said connector 50, and continuously apply force until it thoroughly getting into the space between said two buckling noses 54 and the front edge of said horizontal body plate 53 to finish the fixedly buckling (as shown in the FIG. 8 and each view of the FIG. 9 as well as view E of the FIG. 7); Finally, re-pivot said pivotal cover 40 to snap down on the top surface of said frame hood 30 so as to complete the mounting assembly operation.
Although the conventional connecting device aforesaid can achieve the purpose of jointing the “support frameless wiper” with said traditional hook head of the hook-type wiper arm, there are some drawbacks remain as below:
1. Refer to FIGS. of 10 through 12, during the operation procedure of replacing support frameless wiper 10, said conventional connecting device is always interfered by said pivotal cover 40 and results in being not smoothly; The reason is that said hook-type wiper arm 60 must be in upright position whenever replacing support frameless wiper 10; Namely, apply an upwards force (as shown in the FIG. 10) on said hook-type wiper arm 60 horizontally on the windshield G to let it become upright by the elastic foldable articulation 62 means of fulcrum so as to have said support frameless wiper 10 detached away said windshield G for replacing operation (as shown in the FIG. 11); Hence, said frame hood 30 is always in upright status no matter the procedure of dismounting or mounting operation such that said mating spindle 33 in topmost position to let said pivotal cover 40 freely pivot downwards and interfere with said hook head 61 (as shown with hypothetical line in view H of the FIG. 12); Thereby, during dismounting or mounting operation, said hook head 61 will collide with and may damage said pivotal cover 40 (as shown in view I of the FIG. 12) to cause extra trouble and working time; To avoid such phenomena aforesaid, a cumbersome helper is needed to temporarily hold said pivotal cover 40 (as shown in view J of the FIG. 12); That is big hindrance out of the consideration of the original designer.
2. Refer to FIGS. of 9, 10-A, 13 and 14, a resultant force F will be produced when said hook-type wiper arm 60 swings back and forth on the windshield G; Said hook head 61 will continuously butt and push against two said buckling noses 54 on said connector 50 under the action of vertical component force F1 (as shown in the FIG. 10-A); Finally, said hook head 61 will break away said connector 5 after certain period of time or certain number in swing of said hook-type wiper arm 60 (The procedure is as shown in reverse order of each view of the FIG. 9, namely from view d to view a); The reason is that a gapδ exists between said two left side plate 51 and right side plate 52 with said two left hood panel 31 and right hood panel 32 (as shown in the FIG. 14) to accommodate the displacement of two deformed buckling noses 54 by the butting and pushing from said hook head 61; The breaking away of hook head 61 from said connector 50 is a hidden trouble in the safety of car driving; That is another big drawback out of the safety consideration of the original designer.
3. Refer to FIGS. of 3 and 15 through 17, each of said mating spindle 33 and mating plate 34 is disposed on the front and rear respectively of said frame hood 30 to facilitate the lifting up and closing down of said pivotal cover 40 with itself; The cross section in round shape with smaller area of said mating spindle 33 and the cross section in square shape with larger area of said mating plate 34 make them have different stress strength (as shown in the FIG. 3); Said two snap-fitting noses 39 on said left hood panel 31 and right hood panel 32 are subjected to butting and pushing force from said left side panel 23 and right side panel 24 (as shown in view e of the FIG. 16) so that result in outwards expansion (as shown in view f of the FIG. 16); Meanwhile, both of said mating spindle 33 and mating plate 34 will bear same axial stress f from both of said left hood panel 31 and right hood panel 32 in consequence of the outwards expanding strain in the middle section; Thereby, one end of said mating spindle 33 with smaller area in cross section will break away from said left hood panel 31 and right hood panel 32 (as shown in the FIG. 17) so that damaging said frame hood 30; The situation aforesaid always happens in the mounting procedure and results in low yield; That is the other big drawback out of the consideration of the original designer.